1. Field of the Invention
This invention relates to a chain whose successive link units have two degrees of freedom so that the chain can be pivoted and run in desired directions.
2. Discussion of the Related Art
A roller chain is often used for transmitting a rotational driving force. The roller chain includes inner and outer link plates which are joined one after another by connecting pins. When mounted on a driving sprocket and a driven sprocket which are placed in a common plane, the roller chain can transmit a rotational driving force from the driving sprocket to the driven sprocket.
Although, while such a conventional roller chain is pivotable, its pivoting action is limited to a single plane. Therefore, it has been required that the driving sprocket and the driven sprocket be placed in the same plane, and it has been impossible to place them in other desired relative positions.
The invention provides a solution to the aforementioned problem with the conventional chain. Specifically, it is an object of the invention to provide a chain whose successive link units are connected in such a way that the axes of motion of their joints are successively displaced by 90 degrees from one link unit to another, making it possible to place a driving sprocket and a driven sprocket in other desired relative positions.
According to the present invention, a chain comprises a plurality of link units, each including a pair of link plates and a connection member placed between the link plates at one end of each link unit, wherein the link plates of one link unit are connected end to end with the link plates of another link unit by a connecting pin in such a way that the link units are angularly displaced by 90 degrees from one link unit to another as viewed along the chain, whereby the successive link units of the chain can be alternately moved in two different directions.